Boris Johnson praised Joe Biden’s administration as a “breath of fresh air” on Thursday as the pair put on a display of unity despite Brexit tensions in their first face-to-face meeting.

Despite speculation the US president was preparing to dress down his counterpart over the Northern Ireland Protocol, the leaders traded public compliments rather than veiled threats.

Their meeting in Cornwall, where the G7 summit of world leaders formally begins on Friday, lasted an hour and 20 minutes – longer than planned, according to Downing Street.

Mr Biden called their talks “very productive” and spoke of a “good first full day” in the UK, while Mr Johnson called their discussions “great” and “fantastic”.

Beforehand the pair posed with touched elbows and thumbs up alongside their wives, Jill Biden and Carrie Johnson, who later strolled on the beach with the Johnsons’ son, Wilfred.

EU capitals have been banking on Mr Biden to weigh in on their side over the dispute about how to keep trade flowing on the island of Ireland without physical checks at the land border.

Lord Frost, the UK government minister leading on Brexit, was given a dressing down by the US Embassy last week and urged to tone down his rhetoric on the Northern Ireland Protocol.

But Mr Biden declined to reprimand Mr Johnson in public on Thursday nor, according to Number 10 sources, in private, with their talks said to have been good natured.

Instead the pair signed a detailed agreement, a new version of the 1941 Atlantic Charter which shaped the post-Second World War globe, which listed dozens of areas the UK-US pledged to cooperate on.

Speaking after the talks in Cornwall’s Carbis Bay, Mr Johnson said: “The talks were great. They went on for a long time.

“We covered a huge range of subjects and it’s wonderful to listen to the Biden administration and to Joe Biden because there’s so much that they want to do together with us from security and Nato to climate change. It’s fantastic, it’s a breath of fresh air.”

That last comment will be taken as a sign of relief by Mr Johnson that he is no longer dealing with Donald Trump, whose unpredictable style as US president and willingness to take on allies caused tensions.

Mr Biden said: “We’ve had a good first full day here in the UK. Prime Minister Johnson and I had a very productive meeting. We discussed a broad range of issues on which the United Kingdom and the United States are working in very close cooperation.

“We affirmed the special relationship – that is not said lightly, the special relationship – between our people and renewed our commitment to defending the enduring democratic values that both our nations share that are the strong foundation of our partnership.”

The remarks were much more positive than those delivered 18 months ago when Mr Biden dubbed Mr Johnson after his re-election a “physical and emotional clone” of Mr Trump.

Brussels and London are at loggerheads over the protocol, which imposes customs checks on goods travelling from Britain into Northern Ireland to avoid a hard land border on the island of Ireland.

The Government has warned it will unilaterally extend the temporary waiving of such checks to defend the integrity of the UK, while Brussels is refusing to agree to such an extension.

Emmanuel Macron, the French president, warned on Thursday that he would not renegotiate the terms of the protocol, which was struck in December ahead of Britain’s departure from the EU.

Mr Macron said: “I believe in the power of treaties. I believe in seriousness. Nothing is renegotiable. Everything is applicable.”

But Mr Biden did not publicly weigh in on the side of Brussels on Thursday.

Asked if Mr Biden had told him privately to “crack on” and end the stand-off, Mr Johnson replied: “Well, no he didn’t.”

He added that all sides wanted to “uphold the Belfast Good Friday Agreement and make sure we keep the balance of the peace process going and that’s absolutely common ground”, adding: “I’m optimistic we can do that.”

At one point during a discussion on camera before their meeting, Mr Biden joked that he and Mr Johnson had “both married well above our station”.

Mr Johnson responded:“I’m not going to dissent from that one. I’m not going to disagree with the president there or indeed on anything else, I think it highly likely.”

During their talks, the pair also discussed Harry Dunn, the British teenager killed in a crash after the wife of a US intelligence official drove on the wrong side of the road in Britain.

A government spokesman said: “The PM raised the tragic Harry Dunn case with President Biden and reiterated that the UK wants to see justice done for the family.”